Aim: MicroRNAs (miRNAs) play important roles in the pathogenesis of autoimmune diseases. We studied the intra-renal expression of miRNA targets that were reported to be differentially expressed in peripheral blood or urine between lupus nephritis (LN) patients and normal controls.
Methods: We quantified the expression of in glomerulus and tubulointerstitium of miR-146a, miR-155, miR-198 miR-638 and miR-663 in 42 patients with LN and 10 healthy controls.
Results: As compared with controls, LN patients had lower glomerular expression of miR-638 (P < 0.001) but higher tubulointerstitial expression of this target (P = 0.001). Both glomerular and tubulointerstitial expression of miR-198 were higher in LN patients than controls (P < 0.001). For miR-146a, LN patients only had higher expression in glomerulus (P = 0.005) but not in tubulointerstitium. Tubulointerstitial miR-638 expression was significantly correlated with proteinuria (r = 0.404; P = 0.022) and disease activity score (r = 0.454; P = 0.008), while glomerular miR-146a expressions were correlated with estimated GFR (r = 0.453; P = 0.028) and histological activity index (r = 0.494; P = 0.027).
Conclusion: We found that intra-renal expression of miR-638, miR-198 and miR-146a are differentially expressed between LN patients and normal controls. Furthermore, the degree of change in glomerular miR-146a and tubulointerstitial miR-638 expression correlated with clinical disease severity. The results suggested that these miRNA targets may play a role in the pathogenesis of lupus nephritis.